When I first saw the advertisement for Wedding Crashers, I thought it was a typical frat boy romp, involving two older men who should know better going after all the tasty young things that are grieving over their bleak futures at weddings. It’s the perfect plan.

But the movie advertised in the trailers is very different from the actual film. Wedding Crashers is actually a sappy love story, complete with theories about true love and the harsh reality that two guys who cruise weddings for chicks are a little pathetic. Depending on your perspective, this is actually a good thing (the movie brings something different to a tired genre) or a bad thing (it is not all about drunk girls getting naked).

Jeremy Grey (Vince Vaughn) and John Beckwith (Owen Wilson) are best friends forever. So much so that the night of John’s parents’ death, Jeremy sleeps over to keep him company. Aren’t they sweet? They are also high-powered lawyers, arbitrating nasty divorces. They’d be quite the catch…if it weren’t for the fact that these two guys crash weddings. Their jobs help convey why they’re so cynical about weddings and also how they can charm their way through just about anything. That all changes when they meet the Clearys.

The Clearys are a high-powered political family. Heading the brood of faux-Kennedys is the patriarch (Christopher Walken), his boozing, horny wife Kathleen (Jane Seymour), his gay son Todd (Keir O’Donnell), grandma (Ellen Albertini, who was also in the Wedding Singer and still going strong!), and his three daughters: dutiful Christina (Jennifer Alden), smart and sassy Claire (the delightful Rachel McAdams), and raunchy Gloria (Isla Fisher, in full-blown nut-job mode). John meets Claire at Christina’s wedding and immediately falls in love. There’s just one problem…she’s engaged. Of course.

And the guy she’s engaged to is Zach “The Sack” Lodge (Bradley Cooper), a hyper-masculine jock who likes to beat people up. Zach is a complete cad and it’s up to John, with a little help from Jeremy, to beat the bad guy, get the girl, and live happily ever after. Somewhere in the middle of all this, Jeremy hooks up with the crazy Gloria and decides she’s perfect for him, an ironic twist for the sidekick.

Wedding Crashers is wildly uneven, but most of the time you don’t mind. Vaughn can be too kinetic, Wilson can be too sedate, and Fisher is so overbearing that she starts to annoy the audience. McAdams, however, lights up the screen with her shy smile. Her magnetic personality even excuses Wilson’s incessant mooning over her. And of course, Walken is hilarious whenever he’s on screen.

That said, the movie is way too long. As a sappy romance that starts out as a frat boy comedy, it swings wildly from one genre to the next. Things take a turn for the worse when Chazz Reinhold (Will Ferrell) shows up, but maybe that’s on purpose. Chazz’s appearance heralds John’s awakening that crashing weddings is really lame, and by that time I felt the same way. Fortunately, the movie wraps up shortly after the Anchorman’s arrival.

Wedding Crashers is one of those sneaky movies that is much more clever in concept than it is in practice. Fooling men (who only see the trailers and figure it’s a comedy) and women (who talk to each other about the movie and thus know what it’s actually about) into seeing the same film is a stroke of pure genius. This is probably why Wedding Crashers did so well: it’s a chick flick disguised as a guy’s movie.